Although pre-launch drivers of the GeForce GTX 680 let the GPU run in PCI-Express Gen 3.0 mode on Intel's Sandy Bridge-E HEDT (X79) platforms, the release drivers limited the GPU to PCI-Express Gen 2.0 on the platform. The issue carried on with GeForce GTX 670, and other graphics cards with "Kepler" family of GPUs. NVIDIA cited reasons such as the platform not being PCI-Expres Gen 3.0 "certified" although it supports the 8 GT/s mode. The company assured users that it was working on getting its hardware to work on the Sandy Bridge-E HEDT platform in Gen 3.0 mode, and until it's absolutely certain about reliability, it is forcing PCI-Express Gen 2.0 mode.

NVIDIA released a patch that enables PCI-Express Gen 3.0 mode on Intel Sandy Bridge-E HEDT (X79) platforms, which lets graphics cards based on GeForce Kepler GPUs, such as GeForce GTX 680, GTX 670, etc., take advantage of 8 GT/s per lane system interface bandwidth. The mode could come particularly handy for graphics cards that are installed on electrical PCI-Express 3.0 x8 slots, as they could end up with bandwidth comparable to that of PCI-Express 2.0 x16. The patch should be installed along with the latest stable drivers. To enable the patch, run the executable and reboot the system. To undo the patch later, run the same executable with "-revert" argument in Command Prompt. Use only if stability is not absolutely paramount, or if the hardware is not operating in a mission-critical environment.

the real truth is that NVIDIAs/ATIs GPUs don't correctly abide by PCI-E gen 3 specs an that intel's CPUs don't either, at least that is according to PLX they are the only ones who correctly abide by PCISIG.

you ran 3 + cards? It's only there that it shows. I've been looking for someone else to run these tests, but have not found anyone. I've tried to get cards too ,as you know, but spending that much money on cards doesn't make sense to me, personally, as I want GTX690!

The story goes that the loss of scaling when adding third/fourth cards is due to lack of bandwidth to the GPUs, and between them. But it was done on SB-E, which is not exactly "certified" for PCIe 3.0, so noone knows exactly what the story is here, and what is going on.

"To undo the patch later, run the same executable with "-revert" argument in Command Prompt. Use only if stability is not absolutely paramount, or if the hardware is not operating in a mission-critical environment."

"To undo the patch later, run the same executable with "-revert" argument in Command Prompt. Use only if stability is not absolutely paramount, or if the hardware is not operating in a mission-critical environment."

Why wouldnt stability be paramount in any machine?

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Some prefer performance. See any extreme benchmarking user running LN2.

See, the story is that not all Intel SB-e CPUs are actually capable of running the PCIe domain at PCIe 3.0 speeds. They are all capable of running the encoding method, just not the frequency.

Because of this, it is impossible for nVidia to guarantee that a user's CPU is capable. There is a good chance that it will be, but without Intel confirming PCIe 3.0 for all CPUs(and Intel does not, specifically stating that all amy not run proper speed), there is no way nVidia could provide this "fix" without that little disclaimer.

Now, if the above posted info aobut PCIe 3.0 and multi-GPU has any rel merit, it would really make some sense for nV to provide this patch ASAP, and this really seems to have been what they have done.

the real truth is that NVIDIAs/ATIs GPUs don't correctly abide by PCI-E gen 3 specs an that intel's CPUs don't either, at least that is according to PLX they are the only ones who correctly abide by PCISIG.

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At least when it comes to nVidia cards, they do have the PCI-E 3.0 Logo on them, so they are certified by PCISIG. I'm not sure about AMD, but AFAIK it is only Intel's platform that isn't PCISIG certified which is why they can't say PCI-E 3.0.

At least when it comes to nVidia cards, they do have the PCI-E 3.0 Logo on them, so they are certified by PCISIG. I'm not sure about AMD, but AFAIK it is only Intel's platform that isn't PCISIG certified which is why they can't say PCI-E 3.0.

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I dont think there ever been a official PCI-E 2.0 or 3.0 logo. Just the PCI Express logo.

Both Nvidia and AMD AIBs just slap the PCI-Express (Basic) logo somewhere on the box (Side or Back). Just look at Wizzard reviews for packaging screenshots.

Motherboards are different. Each motherboard maker has their own take on the PCI-E logo. Usually its the official PCI Express (Grey Frame) logo with a gen # added to it on the side or bottom.

I dont think there ever been a official PCI-E 2.0 or 3.0 logo. Just the PCI Express logo.

Both Nvidia and AMD AIBs just slap the PCI-Express (Basic) logo somewhere on the box (Side or Back). Just look at Wizzard reviews for packaging screenshots.

Motherboards are different. Each motherboard maker has their own take on the PCI-E logo. Usually its the official PCI Express (Grey Frame) logo with a gen # added to it on the side or bottom.

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There is a PCI-E 3.0 logo, it is just the PCI-E Logo with a 3.0 after it, and the card has to be PCISIG certified to have that logo. For them to legally say the card is PCI-E 3.0 the card has to be PCISIG certified. That is why Intel can't advertise their platform as PCI-E 3.0, it isn't PCISIG certified.

There is no mention of numeric PCI Express logo on the site nor on there guildline use of logos
Guidelines and usage says basic logo is acceptable for compliance with 1.0 spec and higher. So according to them thats there only PCI Express logo.

If a company chooses to add a number seperate from the logo thats just not part of the certification.
The consumer would have to look them up on the list for 3.0 certification not look for a logo on the box.

There is no mention of numeric PCI Express logo on the site nor on there guildline use of logos
Guidelines and usage says basic logo is acceptable for compliance with 1.0 spec and higher. So according to them thats there only PCI Express logo.

If a company chooses to add a number seperate from the logo thats just not part of the certification.
The consumer would have to look them up on the list for 3.0 certification not look for a logo on the box.

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The part I'm talking about is covered on page 6 of their Guidelines, that states a product can't claim it is compliant with PCISIG standards unless the product in question has passed all compliance testing related to the specification. So, while there isn't a specific 3.0 logo, the product can't use the term PCI-E 3.0 anywhere, even in the documentation, unless it has passed PCISIG compliance testing. NVidia cards use PCI-E 3.0 in their packaging and documentation, which means they passed the compliance tests, and again I'm pretty sure AMD cards are the same. Intel's platform has not and hence you won't see PCI-E 3.0 anywhere in Intel's documentation or packaging. Basically the words "PCI-E 3.0" becomes the logo I was talking about.